This invention relates to anti-friction gearing, especially gearing that utilizes rollers as anti-friction elements. The inventive concept is particularly applicable to worm-wheel gearing, although it may also have application to rotary screw-nut systems or worm-rack systems. General objects of the invention are to provide an anti-friction gearing system that achieves rolling contact of the drive elements, relatively small frictional losses, relatively long service life, minimal noise generation, relatively high load-handling capability, and two-movement direction capability. In the case of worm-wheel gear systems an additional object is to achieve a relatively great speed change between the drive and driven members.
U.S. Pat. Nos. disclosing inventions having general similarities to the instant invention are MacChesney 3,190,138; Sedgwick et al. 3,468,179; Bond 3,489,026; F'Geppert 4,006,646; and Schutz 4,023,433. These patented inventions use ball type anti-friction elements, whereas the present invention contemplates the use of roller type anti-friction elements. Another difference between my invention and most of the prior art inventions is the fact that in my proposed arrangements the anti-friction rollers rotate on fixed rotational axes whereas in the prior art arrangements the anti-friction elements recirculate through endless grooves or passages. I consider my arrangements to be simpler than the prior art.